Hypertension is a main risk factor for atherosclerosis through vascular wall hyperplasia. A recent study reported a new polymorphism (E65 K) in the beta(1) subunit (KCNMB1) gene of the Ca(2+)-dependent potassium channel with a protective effect against the severity of diastolic hypertension, but further data have lead to conflicting results. In order to ascertain the involvement of the E65 K variant in cardiovascular system regulation, the potential association between this mutation and ischaemic heart disease was assessed through a family-based association study (n=302 individuals). Transmission disequilibrium analysis failed to detect any association between this polymorphism and ischaemic heart disease. Although a minor effect cannot be discarded, sample analytical power and negative results do not support a major role for E65 K polymorphism in atherogenic pathologies.